WO2017018161A1

WO2017018161A1 - Pneumatic tire

Info

Publication number: WO2017018161A1
Application number: PCT/JP2016/070218
Authority: WO
Inventors: 正俊栗山
Original assignee: 横浜ゴム株式会社
Priority date: 2015-07-27
Filing date: 2016-07-08
Publication date: 2017-02-02
Also published as: US20180207993A1; CN107709048A; CN107709048B; JP2017024661A; KR20170121223A; DE112016003414T5; KR101947395B1

Abstract

The present invention improves wear resistance performance while maintaining braking performance on wet road surfaces. This pneumatic tire comprises a plurality of main grooves extending along the tire circumferential direction on the tread surface of a tread section. A plurality of ridge sections adjacent to one another in the tire width direction are formed by each of the main grooves. The plurality of main grooves are adjacent to each other in the tire width direction and are formed in a wave shape having a periodic amplitude. Each of the ridge sections formed between each of the wave-shaped main grooves that are adjacent to each other in the tire width direction is provided with: a plurality of lug grooves that intersect the tire circumferential direction and that are arranged in the tire circumferential direction such that both ends thereof communicate with the main grooves; and a narrow zigzag groove that is provided in a zigzag shape to the groove bottoms of the lug grooves, that has a narrower groove width than the lug grooves, and that follows the direction in which the lug grooves extend.

Description

Pneumatic tire

The present invention relates to a pneumatic tire capable of improving wear resistance while maintaining braking performance on a wet road surface.

Conventionally, for example, the pneumatic tire described in Patent Document 1 aims to improve wet performance (braking performance on a wet road surface) and noise performance (noise resistance outside the vehicle). This pneumatic tire has a wavy groove wall having a wavelength and an amplitude on the left and right, and is divided into a plurality of corrugated circumferential grooves extending in the tire circumferential direction and at least one row of adjacent corrugated circumferential grooves. A pneumatic tire having a corrugated land portion, the left and right groove walls of the corrugated circumferential groove have the same wavelength, and the wavy shapes of the left and right groove walls of the corrugated circumferential groove are arranged with a phase difference from each other Of the left and right corrugated grooves defining one row of corrugated land portions, the amplitude of the groove wall on the corrugated land portion side of one corrugated circumferential groove is the groove on the corrugated land portion side of the other corrugated circumferential groove. Greater than wall amplitude.

Conventionally, the heavy-duty pneumatic tire described in Patent Document 2 is intended to improve wet performance (braking performance on wet road surfaces) and uneven wear resistance. This heavy-duty pneumatic tire has shoulder ribs positioned at least on the outermost sides in the tire width direction on the tread by dividing the tread in the tire width direction by at least three main grooves extending zigzag in the tire circumferential direction. And a second rib adjacent to the inner side of the shoulder rib across the main groove, and the zigzag pitch and the swing width of each ridge line facing the main groove between the shoulder rib and the second rib are defined on the outer side in the tire width direction. Reduce towards

Conventionally, the pneumatic tire described in Patent Document 3 aims to improve the performance on ice while maintaining the dry performance and the performance on snow. The pneumatic tire has a pair of center main grooves extending continuously in the tire circumferential direction on both sides of the tire equatorial plane in the tread portion, and continuously extending in the tire circumferential direction outside the center main groove in the tire axial direction. By providing a pair of shoulder main grooves, a center land portion between each center main groove and a middle land portion between the center main groove and the shoulder main groove are provided. Each main groove has a zigzag shape. Each land portion includes a block divided by a plurality of lateral grooves, and the blocks are provided with sipes that communicate with the main groove and extend parallel to each other.

JP 2014-077674 A JP-A-61-175104 Japanese Patent Laid-Open No. 2015-013513

In the pneumatic tire of Patent Document 1 described above, the braking performance on the wet road surface is improved by the corrugations of the left and right groove walls of the corrugated circumferential groove. On the other hand, the rigidity of the land portion is improved in order to improve the wear resistance performance. When it is going to improve, it will become the tendency for the braking performance on a wet road surface to fall. Further, in the heavy-duty pneumatic tire of Patent Document 2 described above, the zigzag pitch and the swing width of each ridge line facing the main groove between the shoulder rib and the second rib are reduced toward the outside in the tire width direction. As a result, a difference in rigidity occurs between the shoulder rib and the second rib, which may reduce the wear resistance. Further, since the main groove has a zigzag shape, uneven wear may occur in the corner portion. Moreover, since the land part is divided | segmented by the horizontal groove and the sipe, the rigidity of the pneumatic tire of patent document 3 mentioned above may fall, and there exists a possibility that abrasion resistance performance may fall.

The present invention has been made in view of the above, and an object of the present invention is to provide a pneumatic tire capable of improving the wear resistance while maintaining the braking performance on a wet road surface.

In order to solve the above-described problems and achieve the object, the pneumatic tire of the present invention has a plurality of main grooves extending along the tire circumferential direction on the tread surface of the tread portion, and each of the main grooves In the pneumatic tire in which a plurality of land portions adjacent in the tire width direction are formed, the plurality of main grooves adjacent in the tire width direction are formed in a wavy shape having periodic amplitudes, and the tire width direction Lug grooves that are provided between the land portions formed between the wavy main grooves adjacent to each other in the tire circumferential direction so that both ends communicate with the main groove and are aligned in the tire circumferential direction. And a zigzag narrow groove provided in a zigzag shape with a groove width narrower than the lug groove along the extending direction of the lug groove, at the groove bottom of the lug groove.

According to this pneumatic tire, since the main groove is formed in a wave shape having an amplitude periodically, the main groove is widened as a whole, drainage is improved, and braking performance on a wet road surface can be maintained. it can. Moreover, according to this pneumatic tire, the drainage is improved by the lug groove and the zigzag narrow groove, while the wear resistance is suppressed by suppressing the rigidity reduction of the land portion divided by the lug groove due to the engagement by the zigzag narrow groove. The performance can be improved.

In the pneumatic tire of the present invention, the zigzag narrow groove has a groove depth of 70% or more with respect to the total groove depth including the groove depth of the lug groove.

According to this pneumatic tire, by making the zigzag narrow groove 70% or more with respect to the total groove depth, the effect of improving drainage and the effect of improving the wear resistance can be remarkably obtained. .

Further, in the pneumatic tire of the present invention, the zigzag narrow groove has at least three or more amplitudes.

According to this pneumatic tire, when the amplitude of the zigzag narrow groove is three or more, the effect of improving the wear resistance can be remarkably obtained.

In the pneumatic tire according to the present invention, four main grooves are provided on the tread surface, and all have periodic amplitudes, and each main groove causes a center land portion and a tire in the center land portion. Middle land portions adjacent to both sides in the width direction and shoulder land portions adjacent to the outer sides in the tire width direction of the respective middle land portions are formed, and the lug grooves are formed in the center land portion and one of the middle land portions. And the zigzag narrow groove is provided, the other middle land portion and each shoulder land portion do not have the zigzag narrow groove, and a plurality of lug grooves arranged in the tire circumferential direction intersecting the tire circumferential direction are provided, The lug groove is arranged on a curved line continuously extending across the land portions between both outer ends of the tread portion in the tire width direction.

According to this pneumatic tire, the drainage between the land portions is good by arranging the lug grooves on the curved line continuously extending across the land portions between both outer ends in the tire width direction of the tread portion. As a result, braking performance on a wet road surface can be maintained. In addition, by placing lug grooves on the curved line that runs smoothly across the land portions between the outer ends of the tread portion in the tire width direction, an extreme rigidity difference occurs between the land portions in the tire width direction. Therefore, the wear resistance can be improved.

The pneumatic tire according to the present invention can improve the wear resistance performance while maintaining the braking performance on a wet road surface.

FIG. 1 is a meridional sectional view of a pneumatic tire according to an embodiment of the present invention. FIG. 2 is a plan view of the tread portion of the pneumatic tire according to the embodiment of the present invention. FIG. 3 is an enlarged cross-sectional view of the main groove of the pneumatic tire according to the embodiment of the present invention. FIG. 4 is an enlarged cross-sectional view of the lug groove of the pneumatic tire according to the embodiment of the present invention. FIG. 5 is an enlarged cross-sectional view of a narrow groove of the pneumatic tire according to the embodiment of the present invention. FIG. 6 is an enlarged cross-sectional view of the lug narrow groove of the pneumatic tire according to the embodiment of the present invention. FIG. 7 is a plan view of a tread portion of another example of a pneumatic tire according to the embodiment of the present invention. FIG. 8 is an enlarged sectional view of a main groove of a pneumatic tire of another example according to the embodiment of the present invention. FIG. 9 is a chart showing the results of the performance test of the pneumatic tire according to the example of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by this embodiment. The constituent elements of this embodiment include those that can be easily replaced by those skilled in the art or those that are substantially the same. Further, a plurality of modifications described in this embodiment can be arbitrarily combined within the scope obvious to those skilled in the art.

FIG. 1 is a meridional sectional view of a pneumatic tire according to this embodiment. FIG. 2 is a plan view of the tread portion of the pneumatic tire according to the present embodiment. FIG. 3 is an enlarged cross-sectional view of the main groove of the pneumatic tire according to the present embodiment. FIG. 4 is an enlarged cross-sectional view of the lug groove of the pneumatic tire according to the present embodiment. FIG. 5 is an enlarged cross-sectional view of a narrow groove of the pneumatic tire according to the present embodiment. FIG. 6 is an enlarged cross-sectional view of the lug narrow groove of the pneumatic tire according to the present embodiment.

In the following description, the tire radial direction refers to a direction orthogonal to the rotation axis (not shown) of the pneumatic tire 1, and the tire radial direction inner side refers to the side toward the rotation axis in the tire radial direction, the tire radial direction outer side. Means the side away from the rotation axis in the tire radial direction. Further, the tire circumferential direction refers to a circumferential direction with the rotation axis as the central axis. Further, the tire width direction means a direction parallel to the rotation axis, the inner side in the tire width direction means the side toward the tire equator plane (tire equator line) CL in the tire width direction, and the outer side in the tire width direction means in the tire width direction. The side away from the tire equatorial plane CL. The tire equatorial plane CL is a plane that is orthogonal to the rotation axis of the pneumatic tire 1 and passes through the center of the tire width of the pneumatic tire 1. The tire width is the width in the tire width direction between the portions located outside in the tire width direction, that is, the distance between the portions farthest from the tire equatorial plane CL in the tire width direction. The tire equator line is a line along the tire circumferential direction of the pneumatic tire 1 on the tire equator plane CL. In the present embodiment, the same sign “CL” as that of the tire equator plane is attached to the tire equator line.

The pneumatic tire 1 is mainly used for a passenger car. As shown in FIG. 1, as shown in FIG. 1, a tread portion 2, shoulder portions 3 on both sides thereof, a side wall portion 4 and a bead successively connected from each shoulder portion 3. Part 5. The pneumatic tire 1 includes a carcass layer 6, a belt layer 7, and a belt reinforcing layer 8.

The tread portion 2 is made of a rubber material (tread rubber), and is exposed at the outermost side in the tire radial direction of the pneumatic tire 1, and the outer peripheral surface thereof is the contour of the pneumatic tire 1. The outer peripheral surface of the tread portion 2 is a surface that can mainly come into contact with the road surface during traveling, and is configured as a tread surface 21.

The shoulder portion 3 is a portion of the tread portion 2 on both outer sides in the tire width direction. Further, the sidewall portion 4 is exposed at the outermost side in the tire width direction of the pneumatic tire 1. The bead unit 5 includes a bead core 51 and a bead filler 52. The bead core 51 is formed by winding a bead wire, which is a steel wire, in a ring shape. The bead filler 52 is a rubber material disposed in a space formed by folding the end portion in the tire width direction of the carcass layer 6 at the position of the bead core 51.

The carcass layer 6 is configured such that each tire width direction end portion is folded back from the tire width direction inner side to the tire width direction outer side by a pair of bead cores 51 and is wound around in a toroidal shape in the tire circumferential direction. It is. The carcass layer 6 is formed by coating a plurality of carcass cords (not shown) arranged in parallel at an angle in the tire circumferential direction with an angle with respect to the tire circumferential direction being along the tire meridian direction. The carcass cord is made of, for example, an organic fiber (polyester, rayon, nylon, etc.). The carcass layer 6 is provided as at least one layer.

The belt layer 7 has a multilayer structure in which at least two

belts

71 and 72 are laminated, and is disposed on the outer side in the tire radial direction which is the outer periphery of the carcass layer 6 in the tread portion 2 and covers the carcass layer 6 in the tire circumferential direction It is. The

belts

71 and 72 are formed by coating a plurality of cords (not shown) arranged in parallel at a predetermined angle (for example, 20 ° to 30 °) with a coat rubber with respect to the tire circumferential direction. The cord is made of, for example, steel or organic fiber (polyester, rayon, nylon, etc.). Further, the overlapping

belts

71 and 72 are arranged so that the cords intersect each other.

The belt reinforcing layer 8 is disposed on the outer side in the tire radial direction which is the outer periphery of the belt layer 7 and covers the belt layer 7 in the tire circumferential direction. The belt reinforcing layer 8 is formed by coating a plurality of cords (not shown) arranged in parallel in the tire circumferential direction (± 5 °) in the tire width direction with a coat rubber. The cord is made of, for example, steel or organic fiber (polyester, rayon, nylon, etc.). The belt reinforcing layer 8 shown in FIG. 1 is disposed so as to cover the end of the belt layer 7 in the tire width direction. The configuration of the belt reinforcing layer 8 is not limited to the above, and is not clearly shown in the figure. However, the belt reinforcing layer 8 is configured to cover the entire belt layer 7 or has two reinforcing layers, for example, on the inner side in the tire radial direction. The reinforcing layer is formed so as to be larger in the tire width direction than the belt layer 7 and is disposed so as to cover the entire belt layer 7, and the reinforcing layer on the outer side in the tire radial direction is disposed so as to cover only the end portion in the tire width direction of the belt layer 7. Alternatively, for example, a configuration in which two reinforcing layers are provided and each reinforcing layer is disposed so as to cover only the end portion in the tire width direction of the belt layer 7 may be employed. That is, the belt reinforcing layer 8 overlaps at least the end portion in the tire width direction of the belt layer 7. The belt reinforcing layer 8 is provided by winding a strip-shaped strip material (for example, a width of 10 [mm]) in the tire circumferential direction.

By the way, as for the pneumatic tire 1 of this embodiment, the direction inside and outside the vehicle when the vehicle is mounted is designated. That is, when the pneumatic tire 1 is mounted on a vehicle, the direction with respect to the inner side and the outer side of the vehicle is specified in the tire width direction. The designation of the direction is not clearly shown in the figure, but is indicated by, for example, an index provided on the sidewall portion 4. When this pneumatic tire 1 is mounted on a vehicle, the side facing the inside of the vehicle is the inside of the vehicle, and the side facing the outside of the vehicle is the outside of the vehicle. In addition, designation | designated of a vehicle inner side and a vehicle outer side is not restricted to the case where it mounts | wears with a vehicle. For example, when the rim is assembled, the direction of the rim with respect to the inside and outside of the vehicle is determined in the tire width direction. Therefore, when the rim is assembled, the pneumatic tire 1 is directed to the vehicle inside and outside of the vehicle in the tire width direction. The direction is specified.

In the pneumatic tire 1 as described above, the tread surface 21 of the tread portion 2 is formed with four main grooves 22 extending along the tire circumferential direction as shown in FIGS. 1 and 2. Yes.

The main groove 22 has two center main grooves 22A provided adjacent to the center in the tire width direction so as to sandwich the tire equatorial plane CL, and shoulders provided on the outer sides in the tire width direction of the respective center main grooves 22A. Main groove 22B. The tread surface 21 has five land portions 23 formed by the main grooves 22. The land portion 23 is provided between each center main groove 22A and disposed on the tire equatorial plane CL. The land portion 23 is provided between each center main groove 22A and each shoulder main groove 22B. The middle land portions 23B adjacent to both outer sides in the tire width direction of the land portions 23A and the outer sides in the tire width direction of the respective shoulder main grooves 22B are adjacent to the outer sides in the tire width direction of the respective middle land portions 23B. Each shoulder land portion 23 C disposed on the outermost side in the tire width direction of the portion 2.

Each main groove 22 (22A, 22B) is formed in a wave shape having a groove width W1 constant in the tire circumferential direction and periodically having an amplitude. The wave shape of each main groove 22 has a periodic amplitude such that the groove bottom 22a shown in FIG. 3 is linear along the tire circumferential direction and the groove wall 22b has a constant groove width W1 in the tire circumferential direction. Can be obtained. The wave shape of each main groove 22 can also be obtained by having the groove bottom 22a and the groove wall 22b shown in FIG. 3 periodically have an amplitude so that the groove width W1 is constant in the tire circumferential direction. In the present embodiment, each main groove 22 has a chamfer 22c formed at the opening edge as shown in FIG. Further, the groove width W1 of the main groove 22 is a width that opens to the tread surface 21, and in the main groove 22 in which the chamfer 22c is formed, the space between the outer edges of the chamfer 22c is the groove width W1. As shown in FIG. 3, the main groove 22 has a groove width W1 of 5 mm or more and 12 mm or less for the center main groove 22A, a groove depth D1 of 4 mm or more and 8 mm or less, and a groove width W1 of 3 mm or more for the shoulder main groove 22B. 6 mm or less and the groove depth D1 is 4 mm or more and 8 mm or less. The groove width W1 is such that the center main groove 22A is larger than the shoulder main groove 22B. For example, the shoulder main groove 22B is within a range of 10% to 50% with respect to the groove width W1 of the center main groove 22A. It is preferable for maintaining the drainability in the main groove 22A and securing the rigidity of the land portion 23 around the shoulder main groove 22B. In addition, as shown in FIG. 2, the main groove 22 has a center line 22d with a center line 22d whose amplitude is within the range of 20% to 30% of the ground contact width TW from the tire equatorial plane CL to the outer side in the tire width direction. The center line 22d of the amplitude of the shoulder main groove 22B is disposed at a distance L2 in the range of 60% to 70% of the ground contact width TW from the tire equatorial plane CL to the outer side in the tire width direction. It is preferable to maintain the drainability in the center main groove 22A and to secure the rigidity of the land portion 23 around the shoulder main groove 22B. And the edge shape of the tire width direction of each land part 23 and a tire width direction dimension are determined with the amplitude of the said main groove 22, and the position of a tire width direction.

Here, the contact width TW is the width in the tire width direction of the contact area. Further, both outermost ends in the tire width direction of the ground contact area are referred to as ground contact ends T. In FIG. 2, the ground contact end T is shown continuously in the tire circumferential direction. The ground contact area is a flat surface in which the tread surface 21 of the tread portion 2 of the pneumatic tire 1 is dried when the pneumatic tire 1 is assembled on a regular rim and filled with a regular internal pressure and 70% of the regular load is applied. This is an area where it touches the ground. The regular rim is “standard rim” defined by JATMA, “Design Rim” defined by TRA, or “Measuring Rim” defined by ETRTO. The normal internal pressure is “maximum air pressure” defined by JATMA, the maximum value described in “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” defined by TRA, or “INFLATION PRESSURES” defined by ETRTO. The normal load is “maximum load capacity” defined by JATMA, the maximum value described in “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” defined by TRA, or “LOAD CAPACITY” defined by ETRTO.

Further, the pneumatic tire 1 of the present embodiment has a groove width narrower than the main groove 22 having the smallest groove width W1 in the middle land portion 23B inside the vehicle, and extends in a straight line along the tire circumferential direction. A groove 24 is provided. The auxiliary groove 24 is provided in the center between the center main groove 22A and the shoulder main groove 22B forming the middle land portion 23B on the vehicle inner side, and the middle land portion 23B on the vehicle inner side is formed in a rib land portion aligned in the tire width direction. To divide. The auxiliary groove 24 has a groove width of 1 mm or more and less than 3 mm, and a groove depth of 4 mm or more and 8 mm or less.

Also, in the pneumatic tire 1 of the present embodiment, each land portion 23 is provided with a lug groove 25 and a narrow groove 26 that intersect with the tire circumferential direction. Here, the lug groove 25 provided in the center land portion 23A is a center land portion lug groove 25A, the lug groove 25 provided in each middle land portion 23B is a middle land portion lug groove 25B, and the lug provided in the shoulder land portion 23C. The groove 25 is a shoulder land lug groove 25C. The narrow groove 26 provided in the center land portion 23A is a center land portion thin groove 26A, the narrow groove 26 provided in each middle land portion 23B is a middle land portion thin groove 26B, and the narrow groove provided in the shoulder land portion 23C. 26 is a shoulder land narrow groove 26C. The narrow groove 26 that communicates with the terminal end of the lug groove 25 and that communicates with the main groove 22 and the auxiliary groove 24 is referred to as a communication thin groove 26E. Further, the pneumatic tire 1 of the present embodiment is provided with the lug narrow grooves 27 in which the lug grooves 25 and the narrow grooves 26 are mixed while the lug grooves 25 and the narrow grooves 26 communicate with each other.

As shown in FIG. 4, the lug groove 25 is formed by a chamfer 25 c with a groove wall 25 b extending from an opening on the tread surface 21 to a groove bottom 25 a. The lug groove 25 has a groove width W2 of 2 mm or more and 4 mm or less, a groove depth D2 of 2 mm or more and 6 mm or less, and is shallower than the main groove 22 and the auxiliary groove 24. Further, as shown in FIG. 5, the narrow groove 26 is formed with a groove wall 26b extending from the opening on the tread surface 21 to the groove bottom 26a along the tire radial direction. The narrow groove 26 has a groove width W3 of 0.4 mm or more and 1.0 mm or less, a groove depth D3 of 3 mm or more and 6 mm or less, and is shallower than the main groove 22 and the auxiliary groove 24. As shown in FIG. 6, the lug narrow groove 27 is formed by forming a narrow groove 26 along the extending direction of the lug groove 25 on the groove bottom 25 a of the lug groove 25. The total groove depth including the depth D2 and the groove depth D3 of the narrow groove 26 is 6 mm or less, which is shallower than the main groove 22 and the auxiliary groove 24. Moreover, it is preferable that the groove depth D3 of the narrow groove 26 of the lug narrow groove 27 is 70% or more with respect to the total groove depth (D2 + D3) including the lug groove 25 in the lug narrow groove 27.

Regarding the lug groove 25, the center land part lug groove 25A provided in the center land part 23A is provided in plural in the tire circumferential direction with each end communicating with each center main groove 22A forming the center land part 23A. The center land portion 23A is divided into a plurality of block land portions arranged in the tire circumferential direction. In the present embodiment, the center land portion lug groove 25A is configured as a lug narrow groove 27 in which the lug groove 25 and the narrow groove 26 are mixed.

The middle land portion lug groove 25B provided in the middle land portion 23B on the vehicle outer side is connected to the center main groove 22A and the shoulder main groove 22B that form the middle land portion 23B on the vehicle outer side, and a plurality of them are provided in the tire circumferential direction. The middle land portion 23 B outside the vehicle is divided into a plurality of block land portions arranged in the tire circumferential direction. Further, the middle land portion lug groove 25B provided in the middle land portion 23B outside the vehicle communicates with the shoulder main groove 22B that forms the middle land portion 23B outside the vehicle, and terminates there. In the present embodiment, the middle land portion lug groove 25B provided in the middle land portion 23B outside the vehicle is configured as a lug narrow groove 27 in which the lug groove 25 and the narrow groove 26 are mixed.

The middle land portion lug groove 25B provided in the middle land portion 23B inside the vehicle has one end communicating with the center main groove 22A forming the middle land portion 23B inside the vehicle, and the other end does not reach the auxiliary groove 24 and is inside the vehicle. Are provided in the middle land portion 23B. Accordingly, the middle land portion 23B inside the vehicle is configured as a rib-like land portion. In the present embodiment, the middle land portion lug groove 25B provided in the middle land portion 23B inside the vehicle is configured as a lug narrow groove 27 in which the end portion is a mixture of the lug groove 25 and the narrow groove 26. A communicating narrow groove 26 E extends from the narrow groove 26 of the groove 27 and communicates with the auxiliary groove 24.

Here, the middle land portion lug groove 25B provided in the middle land portion 23B outside the vehicle and the center land portion lug groove 25A provided in the center land portion 23A are the middle land portion 23B and the center land portion outside the vehicle. Both ends of the center main groove 22A with respect to 23A face each other, and are provided so as to penetrate the center main groove 22A integrally with each other in a plan view. Further, the center land portion lug groove 25A provided in the center land portion 23A and the middle land portion lug groove 25B provided in the middle land portion 23B inside the vehicle are divided into the center land portion 23A and the middle land portion 23B inside the vehicle. The center main grooves 22A between the two are opposed to each other, and are provided so as to penetrate the center main groove 22A integrally with each other in a plan view. Accordingly, the middle land portion lug groove 25B provided in the middle land portion 23B outside the vehicle, the center land portion lug groove 25A provided in the center land portion 23A, and the middle land portion provided in the middle land portion 23B inside the vehicle. The partial lug groove 25B is configured as a through lug groove 25E that integrally penetrates each center main groove 22A. That is, the through lug groove 25E intersects with the tire circumferential direction and continuously penetrates the center land portion 23A and the vehicle outer middle land portion 23B to be provided in the tire circumferential direction, and the vehicle outer middle land portion 23B. One end is opened in the shoulder main groove 22B on the vehicle outer side of the vehicle, passes through the center main groove 22A on the vehicle inner side of the center land portion 23A, and terminates in the middle land portion 23B on the vehicle inner side without reaching the auxiliary groove 24. Is provided.

Each shoulder land portion lug groove 25C provided in each shoulder land portion 23C intersects with the tire circumferential direction and is arranged in a plurality in the tire circumferential direction. The shoulder land portion lug groove 25C has one end opened at a design end E that is an outer end in the tire width direction of the tread surface 21 of the tread portion 2, and the other end is a shoulder main portion on the inner side in the tire width direction of each shoulder land portion 23C. It does not reach the groove 22B and is provided to terminate in the shoulder land portion 23C. Accordingly, each shoulder land portion 23C is configured as a rib-like land portion. In this embodiment, the shoulder land portion lug groove 25C provided in each shoulder land portion 23C is configured as a lug narrow groove 27 in which the end portion is a mixture of the lug groove 25 and the narrow groove 26. A communicating narrow groove 26E extends from the narrow groove 26 and communicates with the shoulder main groove 22B. Further, the terminal end portion configured as the lug narrow groove 27 in the shoulder land portion lug groove 25 C is provided on the ground contact end T.

Here, the design end E refers to the outermost end in the tire width direction of the tread portion 2 on the outer side in the tire width direction of the ground contact end T, and is the outermost end in the tire width direction in which a groove is formed in the tread portion 2. In FIG. 2, the design end E is shown continuously in the tire circumferential direction. That is, in the tread portion 2, on the dry flat road surface, the area closer to the design end E than the ground end T is an area that does not contact the normal road surface.

In addition, each shoulder land part lug groove 25C provided in each shoulder land part 23C is provided to terminate in the shoulder land part 23C, and is provided separately from the above-described through lug groove 25E. However, the shoulder land portion lug groove 25C provided in the shoulder land portion 23C on the outside of the vehicle is an end of the end portion terminated in the shoulder land portion 23C and is one end of the through lug groove 25E. There is an end communicating with the shoulder main groove 22B of the middle land lug groove 25B provided in the portion 23B. The shoulder land lug groove 25C provided in the shoulder land portion 23C on the vehicle inner side is the other end of the through lug groove 25E on the extension of the end portion terminated in the shoulder land portion 23C, and the middle on the vehicle inner side. There is an end of the middle land portion lug groove 25B provided in the land portion 23B. That is, each shoulder land portion lug groove 25C provided in each shoulder land portion 23C, and through lug groove 25E (the middle land portion lug groove 25B of the middle land portion 23B outside the vehicle, the center land portion lug groove of the center land portion 23A) 25A and the middle land portion lug groove 25B of the middle land portion 23B inside the vehicle, each lug groove 25 is formed between the land portions 23A, between the outer ends (design end E) of the tread portion 2 in the tire width direction. It is arranged on the curved line CU smoothly extending across 23B and 23C. Curve CU refers to an angle with respect to the tire width direction at a tangent of each part that is 40 ° or more and 90 ° or less.

Regarding the narrow groove 26, the center land portion narrow groove 26A provided in the center land portion 23A is provided so as to intersect the tire circumferential direction between the center land portion lug grooves 25A adjacent in the tire circumferential direction. The center land portion narrow groove 26A has one end communicating with the center main groove 22A inside the vehicle in the center land portion 23A, and the other end does not reach the center main groove 22A outside the vehicle in the center land portion 23A. It is provided with termination.

The middle land portion narrow groove 26B provided in the middle land portion 23B outside the vehicle is provided so as to intersect the tire circumferential direction between the middle land portion lug grooves 25B adjacent in the tire circumferential direction. The middle land portion narrow groove 26B is provided such that one end thereof communicates with the center main groove 22A in the middle land portion 23B, and the other end does not reach the shoulder main groove 22B in the middle land portion 23B and terminates in the middle land portion 23B. Yes.

The middle land portion narrow groove 26B provided in the middle land portion 23B on the inner side of the vehicle is provided so as to intersect the tire circumferential direction between the extension of the middle land portion lug groove 25B adjacent in the tire circumferential direction. . The middle land portion narrow groove 26B is provided with each end communicating with the shoulder main groove 22B and the auxiliary groove 24 in the middle land portion 23B. Therefore, the middle land portion narrow groove 26B provided in the middle land portion 23B on the vehicle inner side is a block land portion in which a part of the middle land portion 23B between the shoulder main groove 22B and the auxiliary groove 24 is arranged in the tire circumferential direction. Divide into

Each shoulder land portion narrow groove 26C provided in each shoulder land portion 23C is provided so as to intersect the tire circumferential direction between the shoulder land portion lug grooves 25C adjacent in the tire circumferential direction. The shoulder land portion narrow groove 26C communicates with the shoulder main groove 22B at one end, extends beyond the ground contact end T, and near the outer end in the tire width direction (design end E) of the tread portion 2 near the shoulder land portion. It is provided to terminate in 23C.

Each shoulder land portion 23C is provided with a recess 28 in the vicinity of both outer ends (design end E) of the tread portion 2 in the tire width direction. The recesses 28 are formed in a circular dimple shape, and there are two rows in the tire width direction and two tire width direction inner rows 28a in the tire circumferential direction between the shoulder land lug grooves 25C adjacent in the tire circumferential direction. Three tire width direction outer rows 28b are formed in the tire circumferential direction. Moreover, the recessed part 28 is formed in the tire width direction outer side row | line | column 28b larger diameter than the tire width direction inner side row | line | column 28a. Each shoulder land portion narrow groove 26 C provided in each shoulder land portion 23 C is provided with the other end terminated at the recess 28. In the present embodiment, the shoulder land portion narrow groove 26C is provided to terminate at the center recess portion 28 in the tire circumferential direction of the tire width direction outer row 28b.

In the pneumatic tire 1 of the present embodiment, the narrow groove 26 in the lug narrow groove 27 of the center land portion 23A and the middle land portion 23B outside the vehicle is configured as a zigzag narrow groove 26F. The zigzag narrow groove 26F is formed by zigzag forming the narrow groove 26 provided on the groove bottom 25a of the lug groove 25 in the lug narrow groove 27 of the center land portion 23A and the middle land portion 23B outside the vehicle. The zigzag narrow groove 26F is provided in a zigzag shape within the groove width W2 of the center land portion lug groove 25A of the center land portion 23A and the middle land portion lug groove 25B of the middle land portion 23B outside the vehicle. The groove width W3 and the groove depth D3 of the zigzag narrow groove 26F are the same as the narrow groove 26 in the lug narrow groove 27 described above. The zigzag narrow groove 26 F has at least three or more amplitudes in one lug narrow groove 27. In the zigzag narrow groove 26F, one amplitude is formed by a short narrow groove and a long narrow groove, and this amplitude is continuously provided.

Incidentally, FIG. 7 is a plan view of a tread portion of a pneumatic tire of another example of the present embodiment.

The pneumatic tire 101 of another example shown in FIG. 7 is different from the pneumatic tire 1 described above in that a bulging groove 22E is provided in the shoulder main groove 22B on the vehicle inner side, and the center land portion of the center land portion 23A. The narrow groove 26A, the middle land portion narrow groove 26B of the middle land portion 23B on the vehicle outer side, and the shoulder land portion narrow groove 26C of the shoulder land portion 23C on the outer side of the vehicle are between the lug grooves 25 adjacent in the tire circumferential direction. A plurality of circumferentially arranged points, a point provided with a projection 31 in the center main groove 22A, a center land portion narrow groove 26A of the center land portion 23A, and a middle land portion of the middle land portion 23B outside the vehicle The narrow groove 26B and the shoulder land portion narrow groove 26C of each shoulder land portion 23C are provided with holes 32, and the shoulder land portion 23C outside the vehicle is not provided with a recess 28. It made. Hereinafter, although these different points of the pneumatic tire 101 are demonstrated, the same code | symbol is attached | subjected to the equivalent part to the pneumatic tire 1 mentioned above, and the description is abbreviate | omitted.

The bulging groove 22E is provided in a semicircular shape on the middle land portion 23B side inside the vehicle in the shoulder main groove 22B inside the vehicle. The bulging groove 22E is provided to bulge toward the middle land portion 23B at a position facing the communication narrow groove 26E provided in the shoulder land portion 23C inside the vehicle.

A plurality of center land portion narrow grooves 26A are provided side by side in the tire circumferential direction between adjacent center land portion lug grooves 25A in the tire circumferential direction. In the present embodiment, two center land portion narrow grooves 26A are provided side by side in the tire circumferential direction between adjacent center land portion lug grooves 25A in the tire circumferential direction. When a plurality of center land portion lug grooves 25A adjacent to each other in the tire circumferential direction are provided side by side in the tire circumferential direction, one end and the other end of the center land portion narrow groove 26A are arranged in reverse order in the tire circumferential direction. Has been. That is, in FIG. 7, the center land portion narrow groove 26A communicates with the center main groove 22A on the vehicle outer side at the uppermost side, and communicates with the center main groove 22A on the vehicle inner side at the lower side. The one on the side communicates with the center main groove 22A on the vehicle outer side, and the form communicating with the main grooves 22 on both sides in the tire width direction is arranged in reverse order in the tire circumferential direction.

A plurality of middle land portion narrow grooves 26B of the middle land portion 23B on the vehicle outer side are provided side by side in the tire circumferential direction between the middle land portion lug grooves 25B adjacent in the tire circumferential direction. In the present embodiment, two middle land portion narrow grooves 26B of the middle land portion 23B outside the vehicle are provided side by side in the tire circumferential direction between the middle land portion lug grooves 25B adjacent in the tire circumferential direction. When a plurality of middle land portion lug grooves 25B adjacent in the tire circumferential direction are provided side by side in the tire circumferential direction, the middle land portion narrow grooves 26B of the middle land portion 23B on the vehicle outer side are sequentially arranged in the tire circumferential direction. One end and the other end are arranged oppositely. That is, in FIG. 7, the middle land portion narrow groove 26B of the middle land portion 23B outside the vehicle is in communication with the shoulder main groove 22B at the uppermost side and with the center main groove 22A at the lower side. The lower one communicates with the shoulder main groove 22B on the vehicle outer side, and the form communicating with the main grooves 22 on both sides in the tire width direction is arranged in reverse order in the tire circumferential direction.

A plurality of shoulder land portion narrow grooves 26C provided in the shoulder land portion 23C on the outer side of the vehicle are provided side by side in the tire circumferential direction between the shoulder land portion lug grooves 25C adjacent in the tire circumferential direction. In the present embodiment, two shoulder land portion narrow grooves 26C provided in the shoulder land portion 23C on the vehicle outer side are provided side by side in the tire circumferential direction between the shoulder land portion lug grooves 25C adjacent in the tire circumferential direction. ing.

As shown in the enlarged sectional view of the main groove in FIG. 8, the protrusion 31 is provided to protrude from the groove bottom 22a of the center main groove 22A. The protrusion 31 is formed in a hemispherical shape, and is provided so as to protrude smoothly from the groove bottom 22a of the center main groove 22A via a curved surface. A plurality of the protrusions 31 are provided in the tire circumferential direction along the periodic amplitude of the center main groove 22A. Further, the protrusion 31 is provided with a plurality of rows (two rows in this embodiment) provided in the tire circumferential direction along a plurality of rows in the tire circumferential direction along the periodic amplitude. Further, the protrusion 31 is formed so that the protruding height from the groove bottom 22a is lower than the wear indicator (not shown) arranged on the groove bottom 22a of the center main groove 22A. The wear indicator is a protrusion in the main groove 22 in which the degree of tread wear can be visually determined. In the case of a passenger car, the wear indicator is defined as a height of 1.6 mm from the groove bottom 22a. Therefore, the protrusion 31 protrudes from the groove bottom 22a with a height of less than 1.6 mm. Such a protrusion 31 preferably has a hemispherical diameter of 0.4 mm or more and 1.5 mm or less and a protrusion height of 0.2 mm or more and less than 1.6 mm. The protrusion 31 may be provided on the groove bottom 22a of the shoulder main groove 22B. Further, the protrusion 31 may be provided on the groove bottom 22 a of one main groove 22.

The hole 32 is a narrow groove 26, which is a center land portion narrow groove 26A of the center land portion 23A, a middle land portion narrow groove 26B of the middle land portion 23B outside the vehicle, and a shoulder land portion narrow groove of each shoulder land portion 23C. 26C. The hole 32 is a hole that partially expands the groove width of the

narrow grooves

26A, 26B, and 26C. For example, the hole 32 is formed in a circular shape in a plan view, has a diameter of 0.5 mm to 1.0 mm, and a depth. Is preferably 3 mm or more and 6 mm or less. A plurality of the holes 32 are provided along the extending direction of the

narrow grooves

26A, 26B, and 26C, respectively. Further, the center land portion narrow groove 26A of the center land portion 23A and the middle land portion narrow groove 26B of the middle land portion 23B outside the vehicle are provided to terminate in the

land portions

23A and 23B, respectively. A plurality (two in this embodiment) are provided in the middle of the

narrow grooves

26A and 26B, and a total of three are provided in one

narrow groove

26A and 26B. Further, the shoulder land portion narrow groove 26C of the shoulder land portion 23C outside the vehicle has no recess 28 in the shoulder land portion 23C outside the vehicle. Provided, and a plurality of holes 32 are provided in the middle of the shoulder land narrow groove 26C, and a total of four holes 32 are provided in one shoulder land narrow groove 26C. It has been. That is, the center land portion narrow groove 26A of the center land portion 23A, the middle land portion thin groove 26B of the middle land portion 23B outside the vehicle, and the shoulder land portion narrow groove 26C of the shoulder land portion 23C outside the vehicle are terminated at the holes 32. Is provided. Further, the shoulder land portion narrow groove 26C of the shoulder land portion 23C on the vehicle inner side is terminated at the other end with the recess 28, and a plurality of hole portions 32 (two in the present embodiment) are provided in the middle. Two are provided in total in the land narrow groove 26C.

In the hole portion 32, the center land portion 23A and the hole portion 32 provided in the middle land portion 23B outside the vehicle are positioned in the tire width direction with respect to the straight line SL (including the tire equator line CL) along the tire circumferential direction. Are provided side by side in the tire circumferential direction. More specifically, the hole 32 provided in the center land portion 23A and the middle land portion 23B outside the vehicle is partially placed on a straight line SL (including the tire equator line CL) along the tire circumferential direction. A plurality of tires are provided side by side in the tire circumferential direction while shifting their positions in the width direction. A plurality of holes 32 provided in each shoulder land portion 23C are provided side by side in the tire circumferential direction without shifting the position in the tire width direction on the straight line SL along the tire circumferential direction. The middle land portion narrow groove 26B of the middle land portion 23B inside the vehicle does not have the hole portion 32.

As described above, the

pneumatic tires

1 and 101 according to the present embodiment have a plurality of main grooves 22 extending along the tire circumferential direction on the tread surface 21 of the tread portion 2, and the tires are formed by the main grooves 22. In the

pneumatic tires

1 and 101 in which a plurality of land portions 23 adjacent to each other in the width direction are formed, a plurality of main grooves 22 adjacent to each other in the tire width direction are formed in a wavy shape having a periodic amplitude, and the tire width Lugs provided in each land portion 23 formed between the wavy main grooves 22 adjacent to each other in the direction intersecting the tire circumferential direction and having both ends communicating with the main groove 22 and arranged in the tire circumferential direction. The groove 25 and a groove bottom 25a of the lug groove 25 are provided with a zigzag narrow groove 26F that is narrower than the lug groove 25 and provided in a zigzag shape along the extending direction of the lug groove 25.

According to the

pneumatic tires

1, 101, since the main groove 22 is formed in a wave shape having an amplitude periodically, the main groove 22 is widened as a whole to improve drainage, and braking performance on a wet road surface. Can be maintained. Moreover, according to this pneumatic tire 1,101, the drainage is improved by the lug groove 25 and the zigzag narrow groove 26F, while the rigidity of the land portion 23 divided by the lug groove 25 by the meshing by the zigzag narrow groove 26F. The wear resistance can be improved by suppressing the decrease.

In the pneumatic tire 1,101 of the present embodiment, the zigzag narrow groove 26F preferably has a groove depth D3 of 70% or more with respect to the total groove depth including the groove depth D2 of the lug groove 25. .

According to this pneumatic tire 1,101, by making the zigzag narrow groove 26F 70% or more with respect to the entire groove depth, the effect of improving drainage and the effect of improving the wear resistance are remarkably achieved. Obtainable.

Further, in the pneumatic tire 1,101 of the present embodiment, the zigzag narrow groove 26F preferably has at least three or more amplitudes.

According to the

pneumatic tires

1, 101, since the amplitude of the zigzag narrow groove 26F is three or more, the effect of improving the wear resistance can be remarkably obtained. In the zigzag narrow groove 26F, it is preferable that one amplitude is formed by the short narrow groove and the long narrow groove, and this amplitude is provided continuously. By configuring in this way, the lug groove 25 The effect of improving the wear resistance performance by further suppressing the rigidity reduction of the land portion 23 to be divided can be obtained more remarkably.

Further, in the

pneumatic tires

1 and 101 of the present embodiment, four main grooves 22 are provided on the tread surface 21 and all have periodic amplitudes, and the main land 22 has a center land portion 23A and a center. A middle land portion 23B adjacent to both sides in the tire width direction of the land portion 23A and a shoulder land portion 23C adjacent to the outer side in the tire width direction of each middle land portion 23B are formed. ) Are provided with a lug groove 25 and a zigzag narrow groove 26F, and the middle land portion 23B and each shoulder land portion 23C on the other side (the vehicle inside) do not have the zigzag narrow groove 26F and intersect in the tire circumferential direction. A plurality of lug grooves 25 arranged in the tire circumferential direction are provided, and each lug groove 25 is slid across the

land portions

23A, 23B, 23C between both outer ends of the tread portion 2 in the tire width direction. It is preferably arranged on a curve CU leading to or.

According to the

pneumatic tires

1, 101, the lug grooves 25 are arranged on the curved line CU smoothly extending across the

land portions

23A, 23B, 23C between both outer ends of the tread portion 2 in the tire width direction. Moreover, the drainage performance between the

land portions

23A, 23B, and 23C is improved, and the braking performance on the wet road surface can be maintained. Moreover, by arranging the lug groove 25 on the curved line CU smoothly extending across the

land portions

23A, 23B, and 23C between both outer ends of the tread portion 2 in the tire width direction, each land portion 23A in the tire width direction. , 23B, 23C, the wear resistance can be improved.

By the way, the pneumatic tire 101 of this embodiment has a plurality of main grooves 22 extending along the tire circumferential direction on the tread surface 21 of the tread portion 2, and is adjacent to each other in the tire width direction by the main grooves 22. In the pneumatic tire 101 in which a plurality of land portions 23 are formed, at least two main grooves 22 adjacent in the tire width direction are formed in a wave shape having an amplitude periodically, and each of the wavy main grooves 22 is formed. The land portion 23 (the center land portion 23A and / or the middle land portion 23B outside the vehicle) formed between the tires intersects the tire circumferential direction, and both ends communicate with each main groove 22 in the tire circumferential direction. Between the lug grooves 25 (the center land portion lug groove 25A and / or the middle land portion lug groove 25B outside the vehicle) provided side by side and the respective lug grooves 25 adjacent in the tire circumferential direction, with respect to the tire circumferential direction. Cross Comprises a narrow groove 26 having a groove width is provided narrow (center land portion narrow groove 26A and / or the vehicle outer side of the middle land portion fine grooves 26B) than the lug groove 25 are arranged plurality in the tire circumferential direction.

According to this pneumatic tire 101, since the two main grooves 22 adjacent in the tire width direction are formed in a wavy shape having an amplitude periodically, the main grooves 22 are widened as a whole and the drainage is good. Thus, braking performance on a wet road surface can be maintained. Moreover, according to this pneumatic tire 101, the drainage performance is improved by providing a plurality of lug grooves 25 provided at both ends of the wavy main groove 22 and arranged in the tire circumferential direction. The braking performance can be maintained. Moreover, according to this pneumatic tire 101, by providing the narrow grooves 26 between the respective lug grooves 25 adjacent to each other in the tire circumferential direction, the drainage performance is improved and the braking performance on the wet road surface can be maintained. The narrow groove 26 has one end communicating with the main groove 22 and the other end terminating in the land portion 23 and having a narrower groove width than the lug groove 25. Abrasion resistance can be improved by suppressing a decrease in rigidity of the land portion 23.

Further, in the pneumatic tire 101 of the present embodiment, four main grooves 22 are provided on the tread surface 21 and all have periodic amplitudes, and the main land 22 has a center land portion 23A and a center land portion. A middle land portion 23B adjacent to both sides in the tire width direction of 23A and a shoulder land portion 23C adjacent to the outer side in the tire width direction of each middle land portion 23B are formed, and the center land portion 23A and one (the vehicle outer side) It is preferable that the lug groove 25 and the narrow groove 26 are provided in the middle land portion 23B.

According to this pneumatic tire 101, braking performance on a wet road surface is achieved by improving drainage in the center land portion 23A and one middle land portion 23B adjacent to both sides in the tire width direction of the center land portion 23A. Can be more maintained, and by suppressing the lowering of rigidity of the middle land portion 23B adjacent to both sides of the center land portion 23A and the center land portion 23A in the tire width direction, the effect of improving the wear resistance performance is remarkably increased. Obtainable.

Further, in the pneumatic tire 101 of the present embodiment, an auxiliary groove 24 that has a groove width narrower than each main groove 22 and extends linearly along the tire circumferential direction in the middle land portion 23B of the other (vehicle inner side). In addition, a plurality of tire grooves are arranged in the tire circumferential direction so as to intersect each other in the tire circumferential direction and each end communicates with the main groove 22 and the auxiliary groove 24 on the outer side in the tire width direction, and the groove width is provided narrower than the lug groove 25 And a middle land portion narrow groove 26B.

According to the pneumatic tire 101, the middle land portion 23B has a high contribution to drainage, and the middle land portion 23B is provided with the auxiliary groove 24 and the middle land portion narrow groove 26B extending linearly along the tire circumferential direction. By providing, it is possible to improve drainage and improve braking performance on wet road surfaces. In addition, since the auxiliary groove 24 is narrower than the main groove 22 and the middle land portion narrow groove 26B is narrower than the lug groove 25, the rigidity of the middle land portion 23B is suppressed and wear resistance is improved. Can be improved.

Moreover, in the pneumatic tire 101 of the present embodiment, one end of the main land 22 on the inner side in the tire width direction is arranged in the tire circumferential direction so as to cross the tire circumferential direction at the other (vehicle inner side) middle land portion 23B. The middle land portion lug groove 25B provided in the other middle land portion 23B without the other end reaching the auxiliary groove 24 is communicated with the end portion of the middle land portion lug groove 25B and the auxiliary groove 24. It is preferable to provide a continuous narrow groove 26E having a narrower groove width than the middle land lug groove 25B.

According to this pneumatic tire 101, in the other middle land portion 23B, one end communicates with the main groove 22 on the inner side in the tire width direction, and the other end does not reach the auxiliary groove 24 and terminates in the other middle land portion 23B. The middle land portion lug groove 25B is provided, and the communication narrow groove 26E that communicates the end of the middle land portion lug groove 25B and the auxiliary groove 24 is provided, thereby improving drainage and improving braking performance on wet road surfaces. Can be maintained. On the other hand, the middle land portion lug groove 25B is provided to terminate in the middle land portion 23B, and the communication narrow groove 26E has a groove width narrower than that of the middle land portion lug groove 25B. Abrasion resistance can be improved by suppressing a decrease in rigidity of the portion 23B.

Moreover, in the pneumatic tire 101 of this embodiment, it is preferable that the lug narrow groove 27 in which the lug groove 25 and the narrow groove 26 are mixed is interposed between the middle land portion lug groove 25B and the communication narrow groove 26E. .

According to this pneumatic tire 101, the lug narrow groove 27 is interposed between the middle land portion lug groove 25B and the communication narrow groove 26E, whereby the communication portion between the middle land portion lug groove 25B and the communication narrow groove 26E. It is possible to suppress an extreme change in rigidity, and to improve wear resistance.

Further, in the pneumatic tire 101 of the present embodiment, each shoulder land portion 23C intersects with the tire circumferential direction and is arranged in the tire circumferential direction so that the main grooves 22 (shoulder mains) on the inner side of the shoulder land portion 23C in the tire width direction are arranged. Between the shoulder land portion lug groove 25C provided not to reach the groove 22B) and the shoulder land portion lug groove 25C adjacent to the tire circumferential direction, and intersecting the tire circumferential direction, It is preferable to include a shoulder land portion narrow groove 26C having an end portion communicating with the main groove 22 on the inner side in the tire width direction and having a groove width narrower than the shoulder land portion lug groove 25C.

According to the pneumatic tire 101, the shoulder land portion 23C can be drained by the shoulder land portion narrow groove 26C, and the end of the shoulder land portion 23C can suppress a decrease in rigidity of the shoulder land portion 23C. Abrasion resistance can be improved. Moreover, according to the pneumatic tire 101, the shoulder land portion narrow groove 26C can improve drainage and improve the braking performance on a wet road surface. In addition, since the shoulder land portion narrow groove 26C has a narrower groove width than the shoulder land portion lug groove 25C, it is possible to suppress wear reduction of the shoulder land portion 23C and improve wear resistance.

Further, in the pneumatic tire 101 of the present embodiment, in one (land side of the vehicle) shoulder land portion 23C, the shoulder land portion narrow groove 26C is provided between each shoulder land portion lug groove 25C adjacent in the tire circumferential direction. It is preferable that a plurality are provided side by side in the circumferential direction.

According to this pneumatic tire 101, by providing a plurality of shoulder land portion narrow grooves 26C side by side in the tire circumferential direction, it is possible to improve drainage and improve braking performance on wet road surfaces.

In the pneumatic tire 101 of the present embodiment, the end of the shoulder land portion lug groove 25C and the main groove 22 (shoulder main groove 22B) on the inner side in the tire width direction of the shoulder land portion 23C communicate with each other. It is preferable to provide a continuous narrow groove 26E having a narrower groove width than the groove 25C.

According to this pneumatic tire 101, by providing the communication narrow groove 26E that connects the end of the shoulder land portion lug groove 25C and the main groove 22, the drainage performance is improved and the braking performance on the wet road surface is further maintained. can do. On the other hand, the shoulder land portion lug groove 25C is provided to terminate in the shoulder land portion 23C, and the communication narrow groove 26E is provided with a narrower groove width than the shoulder land portion lug groove 25C. The wear resistance performance can be improved by suppressing the rigidity of the portion 23C.

Moreover, in the pneumatic tire 101 of this embodiment, it is preferable that the lug narrow groove 27 in which the lug groove 25 and the narrow groove 26 are mixed is interposed between the shoulder land portion lug groove 25C and the communication narrow groove 26E. .

According to this pneumatic tire 101, the communication portion between the shoulder land portion lug groove 25C and the communication narrow groove 26E is provided by interposing the lug narrow groove 27 between the shoulder land portion lug groove 25C and the communication narrow groove 26E. It is possible to suppress an extreme change in rigidity, and to improve wear resistance.

Further, in the pneumatic tire 101 of the present embodiment, the main groove 22 (shoulder main groove 22B) on the inner side in the tire width direction of the other shoulder land portion 23C (the vehicle inner side) is adjacent to the communicating narrow groove 26E. It is preferable that a bulging groove 22E that bulges on the other (vehicle inner side) middle land portion 23B side is provided.

According to this pneumatic tire 101, the bulging groove 22E is formed by providing the bulging groove 22E that bulges on the other (the vehicle inner side) middle land portion 23B side at a position facing the communication narrow groove 26E. Since it functions as a water reservoir for draining into the communicating narrow groove 26E, drainage is good and braking performance on wet road surfaces can be further maintained.

In the pneumatic tire 101 (1) of the present embodiment, the shoulder land portion 23C has a recess 28 formed at the outer end in the tire width direction, and the shoulder land portion narrow groove 26C has a recess at the outer end in the tire width direction. It is preferably provided to terminate at 28.

According to this pneumatic tire 101, the end of the shoulder land portion narrow groove 26 C on the outer side in the tire width direction is terminated by the recess 28, so that a load is applied to the end portion of the shoulder land portion narrow groove 26 C on the outer side in the tire width direction. In order to prevent the situation, it is possible to improve wear resistance by suppressing a decrease in rigidity of the shoulder land portion 23C.

Further, the pneumatic tire 101 of the present embodiment has a plurality of main grooves 22 extending along the tire circumferential direction on the tread surface 21 of the tread portion 2, and is adjacent to the tire width direction by each main groove 22. In the pneumatic tire 101 in which the plurality of land portions 23 are formed, at least one main groove 22 is formed in a wavy shape having a periodic amplitude, and the groove bottom 22a of the wavy main groove 22 A plurality of protrusions 31 provided in the tire circumferential direction along the periodic amplitude of the main groove 22 are provided.

According to this pneumatic tire 101, since the main groove 22 is formed in a wave shape having an amplitude periodically, the main groove 22 is widened as a whole, drainage is improved, and braking performance on a wet road surface is improved. can do. In addition, according to this pneumatic tire 101, the protrusion 31 provided on the groove bottom 22a of the wave-like main groove 22 causes turbulent flow in the water at the groove bottom 22a of the main groove 22 and causes water to flow outside the main groove 22. Since the water is diffused and discharged, the drainage performance is improved, and the braking performance on a wet road surface can be improved.

Moreover, in the pneumatic tire 101 of this embodiment, it is preferable that the protrusions 31 are provided in a plurality of rows in the tire width direction.

According to this pneumatic tire 101, by providing a plurality of rows of protrusions 31 in the tire width direction, water is diffused and discharged to both outer sides of the main groove 22 in the tire width direction. The braking performance can be improved.

Further, in the pneumatic tire 101 of the present embodiment, it is preferable that the protrusion 31 is formed with a protrusion height from the groove bottom 22 a lower than that of the wear indicator disposed on the groove bottom 22 a of the main groove 22.

According to this pneumatic tire 101, the wear indicator is a protrusion in the main groove 22 in which the degree of tread wear can be visually determined, and the protrusion height of the protrusion 31 from the groove bottom 22a is lower than the wear indicator. By doing so, it is possible to prevent the protrusion 31 from interfering with the function of the wear indicator.

Further, in the pneumatic tire 101 of the present embodiment, four main grooves 22 are provided on the tread surface 21 and all have periodic amplitudes, and the main land 22 has a center land portion 23A and a center land portion. A middle land portion 23B adjacent to both sides in the tire width direction of 23A and a shoulder land portion 23C adjacent to the outer side in the tire width direction of each middle land portion 23B are formed, and the center land portion 23A and the middle land portion 23B are It is preferable that the protrusions 31 are provided in the main grooves 22 (center main grooves 22A).

According to the pneumatic tire 101, the center land portion 23A at the center of the tread surface 21 is a land portion that contributes to braking performance on a wet road surface, and the middle land portion 23B that forms both sides of the center land portion 23A. By providing the projections 31 with good drainage in each of the main grooves 22 between them, the effect of improving the braking performance on wet road surfaces can be remarkably obtained.

Further, the pneumatic tire 101 of the present embodiment has a plurality of main grooves 22 extending along the tire circumferential direction on the tread surface 21 of the tread portion 2, and is adjacent to the tire width direction by each main groove 22. In the pneumatic tire 101 in which a plurality of land portions 23 are formed, the main groove 22 is formed in a wavy shape having a periodic amplitude, and intersects the land portion 23 with respect to the tire circumferential direction. A plurality of lug grooves 25 arranged side by side in the direction and the lug grooves 25 adjacent to each other in the tire circumferential direction intersect with the tire circumferential direction and are arranged in the tire circumferential direction. A narrow groove 26 having a narrow width and a plurality of holes 32 formed in the narrow groove 26 are provided.

According to this pneumatic tire 101, since the main groove 22 is formed in a wave shape having an amplitude periodically, the main groove 22 is widened as a whole, drainage is improved, and braking performance on a wet road surface is maintained. can do. Moreover, according to the pneumatic tire 101, the drainage is improved by the lug grooves 25 and the narrow grooves 26, while the rigidity of the land portion 23 is reduced in the narrow grooves 26 that are narrower than the lug grooves 25. It is possible to improve the wear resistance performance by suppressing the pressure, and to improve the drainage while maintaining the effect that the hole portion 32 suppresses the rigidity reduction of the land portion 23 due to the narrow groove 26, so that the wet road surface The braking performance can be maintained.

Further, in the pneumatic tire 101 of the present embodiment, four main grooves 22 are provided on the tread surface 21 and all have periodic amplitudes, and the main land 22 has a center land portion 23A and a center land portion. A middle land portion 23B adjacent to both sides in the tire width direction of 23A and a shoulder land portion 23C adjacent to the outer side in the tire width direction of each middle land portion 23B are formed, and the center land portion 23A and one (the vehicle outer side) The middle land portion 23B is provided with a plurality of narrow grooves 26 having hole portions 32 arranged in the tire circumferential direction. One end of the narrow groove 26 having the hole portions 32 communicates with one main groove 22 and the other end of the other. It is preferable that the main groove 22 is not reached but is terminated in the land portion 23, and one end and the other end are alternately arranged in the tire circumferential direction in the tire circumferential direction.

According to this pneumatic tire 101, the center land portion 23A and one (outside of the vehicle) middle land portion 23B are the land portions 23 that contribute to the braking performance of the wet road surface, and the holes 32 in the

land portions

23A and 23B. By providing a plurality of the narrow grooves 26 having the side-by-side in the tire circumferential direction, the drainage performance is improved, and the braking performance on a wet road surface can be improved. On the other hand, the other end of the narrow groove 26 having the hole portion 32 is terminated in the land portion 23, and one end and the other end are alternately arranged in the tire circumferential direction so as to be reversed in the tire width direction. The wear resistance can be improved by making the rigidity uniform.

Further, in the pneumatic tire 101 of the present embodiment, the hole portion 32 provided in the center land portion 23A and one (the vehicle outer side) middle land portion 23B is in the tire width direction with respect to the straight line SL along the tire circumferential direction. It is preferable that a plurality of tires are provided side by side in the tire circumferential direction while shifting their positions.

According to the pneumatic tire 101, the hole 32 is provided with a position shifted in the tire width direction with respect to the straight line SL along the tire circumferential direction, so that the tires are arranged between the narrow grooves 26 aligned in the tire circumferential direction. Generation | occurrence | production of the crack which the hole parts 32 connect in the circumferential direction can be suppressed.

Further, in the pneumatic tire 101 of the present embodiment, the hole portion 32 provided in the center land portion 23A and the middle land portion 23B on one side (the vehicle outer side) is partially placed on the straight line SL along the tire circumferential direction. It is preferable that a plurality of tires are provided side by side in the tire circumferential direction while shifting their positions in the tire width direction.

According to the pneumatic tire 101, the hole 32 is provided with a position shifted in the tire width direction with respect to the straight line SL along the tire circumferential direction, so that the tires are arranged between the narrow grooves 26 aligned in the tire circumferential direction. Generation | occurrence | production of the crack which the hole parts 32 connect in the circumferential direction can be suppressed. On the other hand, the hole 32 is partially provided on the straight line SL along the tire circumferential direction, so that the center land portion 23A and one (vehicle outer side) due to the displacement of the hole 32 in the tire circumferential direction are provided. ) Of the middle land portion 23B can be suppressed, and the wear resistance can be improved.

Further, in the pneumatic tire 101 of the present embodiment, it is preferable that the narrow groove 26 having the hole 32 is provided in each shoulder land portion 23C.

According to this pneumatic tire 101, each shoulder land portion 23C has good drainage due to the narrow groove 26, while the shoulder land portion 23C has a narrow groove width narrower than the lug groove 25. By suppressing the decrease in rigidity, it is possible to improve the wear resistance performance, and to improve the drainage while maintaining the effect that the hole 32 suppresses the decrease in rigidity of the land portion 23 by the narrow groove 26, The braking performance on the wet road surface can be maintained.

Moreover, in the pneumatic tire 101 of the present embodiment, it is preferable that a plurality of the hole portions 32 provided in the shoulder land portion 23C are provided side by side in the tire circumferential direction on the straight line SL along the tire circumferential direction.

According to this pneumatic tire 101, it is possible to improve wear resistance performance by suppressing nonuniform rigidity of the shoulder land portion 23C due to the displacement of the hole portion 32 in the tire circumferential direction.

Further, in the pneumatic tire 101 of the present embodiment, an auxiliary groove 24 that has a groove width narrower than each main groove 22 and extends linearly along the tire circumferential direction in the middle land portion 23B of the other (vehicle inner side). The middle land portion narrow groove 26B, which has an end portion communicating with the main groove 22 and the auxiliary groove 24 on the outer side in the tire width direction and has a groove width narrower than the lug groove 25 and does not have the hole portion 32, It is preferable to provide.

According to the pneumatic tire 101, the middle land portion 23B has a high contribution to drainage, and the middle land portion 23B is provided with the auxiliary groove 24 and the middle land portion narrow groove 26B extending linearly along the tire circumferential direction. By providing, it is possible to improve drainage and improve braking performance on wet road surfaces. Moreover, the middle land portion narrow groove 26B does not have the hole portion 32 due to the presence of the auxiliary groove 24, thereby suppressing the lowering of rigidity of the middle land portion 23B and improving the wear resistance performance.

In this example, performance tests on wear resistance and braking performance on wet road surfaces were performed on a plurality of types of test tires with different conditions (see FIG. 9).

In this performance test, a pneumatic tire with a tire size of 205 / 55R16 is assembled to a regular rim of 16 × 6.5J, filled with a regular internal pressure (200 kPa), and a test vehicle (1600cc front engine front drive sedan type passenger vehicle) Attached to.

Wear resistance performance is evaluated by measuring the amount of wear on each land portion based on the remaining groove amount after running 5000 km on a dry road test course using the test vehicle. Then, based on this measurement result, index evaluation using the conventional example as a reference (100) is performed. In this evaluation, the larger the value, the less the wear and the better.

The method for evaluating the braking performance on wet roads is to measure the braking distance from a speed of 100 km / h on a test course on a wet road with a water depth of 1 mm using the test vehicle. Then, based on this measurement result, index evaluation using the conventional example as a reference (100) is performed. In this evaluation, the larger the numerical value, the shorter the braking distance is preferable.

In FIG. 9, a pneumatic tire as a test tire has four main grooves formed on the tread surface, five land portions, and the land portion is a center land portion disposed on the tire equator surface. The middle land portion is disposed adjacent to both outer sides in the tire width direction of the center land portion, and the shoulder land portion is disposed adjacent to the outer side in the tire width direction of each middle land portion.

In the conventional pneumatic tire shown in FIG. 9, the main groove has a wave-like amplitude. In the conventional pneumatic tire, both ends of the lug groove in the center land portion and the middle land portion outside the vehicle communicate with the main groove. In the pneumatic tire of the comparative example, the main groove oscillates in a wave shape, both ends of the lug groove of the center land portion and the middle land portion outside the vehicle communicate with the land portion, and the lug groove is configured as a lug narrow groove. .

On the other hand, in the pneumatic tires of Examples 1 to 8 shown in FIG. 9, the main groove has a wave-like amplitude, both ends of the lug groove communicate with the main groove, and the lugs of the center land part and the middle land part outside the vehicle Both ends of the groove communicate with the main groove, and at least one of the lug grooves is configured such that the narrow groove at the groove bottom is a zigzag narrow groove. In the pneumatic tires of Examples 4 to 8, the ratio of zigzag narrow grooves to the total groove depth is 70% or more. In the pneumatic tires of Examples 6 to 8, the zigzag narrow groove has three or more amplitudes. In the pneumatic tire of Example 8, the lug grooves are arranged on a curve.

As shown in the test results of FIG. 9, it can be seen that the pneumatic tires of Examples 1 to 8 have improved wear resistance and maintained braking performance on wet road surfaces.

1,101 Pneumatic tire 2 Tread portion 21 Tread surface 22 Main groove 22A Center main groove 22B Shoulder main groove 23 Land portion 23A Center land portion 23B Middle land portion 23C Shoulder land portion 25 Lug groove 25A Center land portion lug groove 25B Middle land Part lug groove 25C shoulder land part lug groove 26F zigzag narrow groove

Claims

In the pneumatic tire in which the tread surface of the tread portion has a plurality of main grooves extending along the tire circumferential direction, and each of the main grooves forms a plurality of land portions adjacent in the tire width direction.
A plurality of the main grooves adjacent to each other in the tire width direction are formed in a wave shape having an amplitude periodically,
Each land portion formed between the wavy main grooves adjacent to each other in the tire width direction intersects with the tire circumferential direction, and a plurality of both ends communicate with the main groove and are arranged side by side in the tire circumferential direction. Lug groove,
A zigzag narrow groove provided in a zigzag shape along the extending direction of the lug groove, the groove width being narrower than the lug groove at the groove bottom of the lug groove,
A pneumatic tire characterized by comprising:
2. The pneumatic tire according to claim 1, wherein the zigzag narrow groove has a groove depth of 70% or more with respect to a total groove depth including a groove depth of the lug groove.
The pneumatic tire according to claim 1 or 2, wherein the zigzag narrow groove has at least three or more amplitudes.
Four main grooves are provided on the tread surface, and all have periodic amplitudes. With each main groove, a center land portion and a middle land portion adjacent to both sides of the center land portion in the tire width direction are provided. , A shoulder land portion adjacent to the outer side in the tire width direction of each middle land portion is formed,
The center land portion and one middle land portion are provided with the lug groove and the zigzag narrow groove,
The other middle land portion and each shoulder land portion are provided with a plurality of lug grooves arranged in the tire circumferential direction intersecting the tire circumferential direction without the zigzag narrow groove,
4. Each of the lug grooves is arranged on a curved line continuously extending across the land portions between both outer ends of the tread portion in the tire width direction. Pneumatic tire described in one.